ABSTRACT: Results of research on copper nanoparticles influence on index of readiness to apoptosis and structural changes of liver, spleen, kidney tissues as well as sensomotor cerebral cortex under copper multiple introductions into organism of animals are presented in the article. It is established that copper nanoparticles distribute in organs and tissues of animals and cause specific structural changes. The increase of copper nanoparticles in organism up to toxical threshold (maximum tolerated dose) results in dystrophy and tissue necrosis. Accurate expression enhancement of Caspase 3 in micro-gliocytes (brain macrophages) has been registered seven days after one-fold intramuscular introduction of copper nanoparticles (dose 2 mg/kg of animal body weight), in liver cells - three and seven days after three-fold intramuscular introduction of copper nanoparticles (total dose was 6 mg/kg of animal body weight), in proximal kidney tubules-three hours, one, three and seven days after three-fold intramuscular introduction of copper nanoparticles (with total dose 6 mg/kg of animal body weight), in spleen cells three hours, one, three and seven days after 12-fold intramuscular introduction (with total dose 24 mg/kg of animal body weight). Received data enables us to propose using index of cells readiness to apoptosis defined by Caspase 3 expression as a criterion for copper nanoparticles introduction safety assessment.